Method of bronze or brass treatment and application



Oct. 10, 1933. H, GANNETT 1,929,739

M OF RONZE 0R BRAS REATME APPLICATION Filed April 4, 1932 1711/8116? 44MZ V Patented ct. 10, 1933 PATENT OFFICE LMETHOD @F BRONZE R BRASS TREAT-MEN'E AND APPLICATION My invention relates broadly to the method oftreating bronze or brass designed for use in contact members whereabrasive conditions exist; the treatment being intended where the con- 6tact members may be entirely made of bronze or brass, or where the outercontact or wear receiving surfaces of such members consist of bronze orbrass which may be integrally united with the supporting metallic bodyportion of the members.

The object of my invention is the provision of contact members whoserubbing or contacting surfaces will be greatly hardened beyond theiroriginal hardness by mechanical or manual working and the life of themembers thereby greatly enhanced.

My invention, more specifically stated, consists in subjecting a unit ofbronze or brass to a mechanical or manual working, namely subjecting thebronze or brass to a compacting action either by means of suitablepressure rolls or hammer blows, whether manually or mechanicallyapplied, whereby the hardness of the bronze or brass is greatlyincreased beyond its native hardness and its resistance to abrasion orwear materially increased.

As a specific embodiment or application of the invention, I have chosento illustrate the application and use of my invention in connection withthe bull-ring of a piston as employed in a locomotive cylinder; thefigure in the drawing being a sectional View of a piston provided with abullring involving the invention; the piston-rod and the usual packingrings for the piston being omitted.

In the exemplification, the main body of the bull ring 10 may be of theconventional type at present in use, with'its perimeter provided withthe grooves or parallely arranged channels 11 in which the usual packingrings (not shown) which are usually sectional, are mounted andheld toprovide constant and proper contact with the lining or bushing in thelocomotive cylinder.

As the locomotive cylinders are generally horizontally disposed, theweight of the bull-rings causes the lower segmental portion of the ringto very quickly become worn and the usefulness of the ring destroyed,with the result that the bull-rings of locomotive cylinders requirefrequent periodical replacement.

In many instances, these replacements are re-' quired in periods oftwenty to thirty days or so and hence entailing a great expense forrailas roads both in the cost and labor'of renewal or replacement of thebull-rings as well as in the loss of service time of the locomotive.

I have found in actual practice that the life and usefulness of thebull-rings will be extended for a long period beyond the useful lifethereof, 6 by building up the worn segmental portion of the bull-ringwith bronze as shown at 12 in the drawing. The bronze is integrallyunited with the cast metal ring by welding; the bronze beingautogenously applied to the ring on opposite sides of the packing-ringchannels or grooves 11, in gradually increasing thickness toward thelower side of the bull-ring in keeping with: the worn condition of thering, as for example indicated by the dotted line 13 in the drawing. 79

These sections or layers of bronze of increasing cross-sectionaldimensions or thickness are separately applied to the bull-ring outerface by welding the same so as to build up the bull-ring, or the renewedsegment thereof, somewhat beyond its normal circumference, say from aneighth to a quarter of an inch in thickness greater than the finaldiametrical thickness of the ring at this point.

After a sufficient quantity of the bronze or brass has been applied, theapplied layer of the bronze is then hammered throughout its entire areafor the purpose of closing the pores therein and to eradicate orcompress the pockets that may be produced therein by oil or gases whichooze from the cast iron portion of the ring during the application ofthe bronze thereto.

The added segments of bronze are then trued down, say to withinone-sixteenth of its finished size and the bronze again subjected toproper pressure, which, on a bull-ring, is best obtained by hammeringthe entire areas of the segments for the purpose of hardening thebronze. It has been found in practice that this is best accomplished byplacing the bull-ring in a lathe where it can be rotated and an airhammer, or other power driven hammer, used so as to cause the entirebody of the bronze to be compacted, namely so as to induce a hardeningbeneath the outer surface as well. That is to say, the bronze issubjected to sufficiently heavy blows so as to thoroughly compact itsmolecules. 1

The hammering of the bronze is preferably done when the bronze hascooled or is cold because the Brinnell hardness of the metal is thenvery materially increased and as a result the life of the bull-ring isgreatly enhanced.

After the second hammering of the bull-ring segments, they are thenmachined'to remove the uneven surfaces produced by the action of theher.

I have found in practice that manganese bronze is best adapted for thispurpose, although other types of bronze or brass may be used and treatedin the same manner.

While I have shown and described my invention in connection with thebull-ring of the piston for use in the steam cylinders of a locomotive,it is apparent that the application and treatment may be otherwiseemployed, as for example the shoes or gibs of the cross-heads of a.locomotive may be made of bronze or brass of a suitable character havingthe desired ingredients. The shoes, like the segmental lower portion ofthe bull-ring, may be welded onto the upper and lower sliding surfacesof the cross-head and hammered as heretofore described and then machined down to proper dimensions. The nonmagnetic bronze or brass willeliminate the wear at present encountered with cross-heads which isgreatly due to the abrasive action of the fine metal particles thatresult from the frictional contact between the cross-head and theguidebars and which metal particles, due to the magnetic metal used,enter between the contacting surfaces of the bars and cross-head. Thisdifiiculty can be eliminated and the life of the crosshead greatlyincreased. and at the same time a considerable saving in lubricantobtained.

Then, too, considerable difficulty is at present encountered with thewear and breakage of journal-box brasses and particularly the wear andbreakage that now occurs at the lower or depending side portions of thebrasses resulting from the lateral impacts and frictional action of thejournals. This dimculty may also be eliminated by subjecting thebrasses, at least the side depending portions thereof, to an amplepressure or hammer blows whereby the entire transverse area of the brassis compacted throughout its thickness.

Attempts at brazing certain elements, as for example bull-rings, havebeen made, but these have been found a failure, because the thin coatingof bronze was not capable of withstanding ab= rasive resistance andconsequently the side edges of the brazed or soldered coating,especially adjacent to the packing ring receiving grooves, would soonburr over and thereby lock the pack= ing rings against proper action andhence resulted in engine failure. On the other hand, by welding aninitially large quantity of bronze or brass onto the supporting body orelement and then subjecting it to proper pressure or hammer blows, thebronze or brass is brought to a hardness extremely beyond its naturalhardness and. hence its use for purposes not heretofore known,

where abrasive conditions exist, is made possible.

I have defined what is believed, from actual experience, to be the bestmethod of treatment, which has been described in terms of descriptionand not in terms-of limitation, as certain modifications may be possiblewithout, however, departing from the spirit of my invention.

What I claim is:

l. The herein described method and application to a horizontallydisposed cast metal bullring of a steam cylinder which consists inbuilding up the lower wear receiving segmental portion of the bull-ringby welding bronze thereon to an initial thickness greater than that ofthe upper cast metal segmental portion, subjecting the applied bronzeportion to pressure so as to close the ports therein, truing the appliedbronze to dimensions somewhat greater than the crosssectional dimensionsof the intended dimensions; then again subjecting the bronze to ahardening pressure and then machining said portion.

2. The herein described method which consists in applying bronze to thewear receiving surface of a bull-ring by welding the bronze to the castmetal ring in thickness greater than the ultimate thickness of the ring;hammering the welded bronze to close the pores; truing the welded bronzedown to a thickness somewhat greater than the ultimate circumferentialdimensions of the ring; and again hammering the welded bronze, down tosubstantially the circum= ferential dimensions of the ring, to densifythe molecular nature of the bronze.

3. The herein described method which consists in autogenously applying amass of bronze to the wear receiving surface of a piston to a thicknessgreater than the desired ultimate thickness of the piston, and thensubjecting the applied mass after it has cooled below the temperature ofthe autogenous application to pore-closing and densifying operationsuntil the mass has been reduced to the desired dimensions whereby a hardwear resisting surface is provided and retained.

i. The herein described method which consists in autogenously applying amass of bronze or brass to the wear receiving surface of a piston orpiston bull-ring operable in a horizontally disposed cylinder to athiclmess greater than the desired ultimate thickness of the piston orbullring, and then subjecting the applied mass to pore-closing andhardening pressure after the mass has cooled below the temperature ofthe autogenous application until the mass has been reduced to thedesired dimensions whereby a hard wear resisting surface is provided andretained. HOMER E. GANNETT.

CERTIFICATE OF CORRECTION.

rmm no. 1,929,739. October 10, 1933.

HOMER E. GANNETT.

it ia hereby certified that error appears in the printed specificationof the above numbered patent requiring correction as follows: Page 2,line 92, claim 1, for "ports" read pores; and that the said LettersPatent should be read with this correction therein that the same mayconform to the record of the case in the Patent Office.

Signed and aealed 'thia 12th day of December, A. D. 1933.

i. M. Hopkine "(Sean Acting Commissioner of Patente.

